Disable the low disk space popup warning in windows 10

To disable these balloon messages follow the steps below:

1. Open the Registry Editor by clicking on Start -> Run and running REGEDIT.

2. Navigate to the following location:

HKEY_CURRENT_USER\Software\Microsoft\ Windows\CurrentVersion\Policies\Explorer

3. Right-click in the blank area of the right-hand pane of the Registry Editor and create a new DWORD Value by selecting New -> DWORD Value.

4. Name this new DWORD Value NoLowDiscSpaceChecks

5. Double-click on the new DWORD value and assign it a value of 1.

6. Close the Registry Editor and restart the computer.

For more information on this refer this Microsoft page